Means for shaping the operative surfaces of grinding wheels



Nov. 1, 1938. A. SCRIVENER MEANS FOR SHAPING THE OPERATIVE SURFACES OF GRINDING WHEEILS Filed Jan. 15; 1937 3 Sheets-Sheet l Nov. 1, 1938. A. SCRIVENER 2,135,202

MEANS FOR SHAPING THE OPERATIVE SURFACES OF GRINDING WHEELS Filed Jan. 15, 1957 s Sheets-Sheet 2 HHHTHHV Nov. 1, 1938.

Patented Nov. 1, 1938 UNITED STATES PATENT OFFICE MEANS FOR SHAPING THE OPERATIVE SURFACES OF GRINDING WHEELS Arthur Scrivener, Birmingham, England 2 Claims.

This invention relates to a new or improved method and. means of shaping the annularly grooved operative surfaces of grinding wheels for helically grooved work such as screw-threads,

5 and is designed to form these annularly grooved operative surfaces in such a manner as to be adapted to produce work which shall be correct in form, particularly with regard to the interference which arises when grinding such heli- 10 cally grooved surfaces.

The invention is characterized by the use of an annularly grooved crushing or shaping roller which is so mountedas to be adapted for a' swivelling adjustment, relative to the axis of ro- 15 tation of the grinding wheel to be operated on,

for the purpose of accommodating itself to the helix angle of the work to be eventually ground,

and which roller is slidable to and from the operative surface of the grinding wheel in direc- 20 tions at right angles to said axis, and is further adapted for a tangential oscillating or sliding movement across the face of the wheel in a direction also at right angles to said axis, for the purpose of compensating for the non-uniform nor- 25 mal contact due to the oblique setting of the crushing or shaping roller and of ensuring a uniform cutting or shaping action of said roller from one end to the other.

In order that the invention may be clearly '30 understood and readily carried into practice,

reference may-be had to the appended explanatory drawings, in which:.

- Figure 1 is an end elevation of a machine incorporating the shaping mechanism in accord- 35 ance with the invention, in conjunction with a diamond trueing attachment.

Figure 2 is a sectional planet the trueing and shaping machine illustrated in Figure 1.

Figure .3 is a sectional end elevation of a" 40 part of the mechanism illustrated in Figures 1 and 2.

Figure 4 is a diagram illustrating the obliquely swivelled setting ofthe crushing or shaping roller, and also the annular grooves formed upon the 45 grinding wheel thereby. 1

Figure 5 is a cross-section taken on the line V--V of Figure 1, further illustrating the means of forward and rearward adjustment of theslide which carries the crushing or shaping roller and 50 its swivelling and oscillating mechanism.

Figure 6 is a partly sectional face view of the swiveiling adjustment mechanism, as seen in the direction indicated at line VI-VI in Figure 1.

In a convenient method of carrying the inventioninto effect, a horizontal slide-way a is provided on the machine frame b at right angles to the axis of the grinding wheel c to be trued, and upon this slide-way a is mounted a box-like slide it which is movable to and from the operative surface of the grinding wheel bymeans of a hand-wheel e and screw 1 operating in conjunction with a nut f. This slide d carries a shaft 9 mounted on anti-friction bearings h, the axis of this shaft 9 being parallel to the axis of the wheel c to be trued. Secured to the end of the 10 shaft g in opposed relation to the grinding wheel 0 is a sleeve 1 having a circular flange 9' upon which is rotatably mounted a bifurcated bracket k having a corresponding circular flange I, see Figure 6, this bracket It being capable of rotational adjustment about an axis at right angles to the axis of the shaft g, under control of a pair of screw studs m operating through arcuate slots n Y in the bracket flange l, and fine adjustment of this setting being obtained by means of a pair of 1 screws 0 which bear upon opposite sides of a peg p projecting from a peripheral part of the flange 7' into a recess q formed in the bracket flange l. Mounted within the bifurcated bracket is is a crushing roller 1' which is free to rotate on ballbearings s about the axis of a spindle t, this crushing roller r having on its peripheral surface a number of annular grooves u of a crosssection corresponding to that of the grooves required on the finished work-piece. The shaft 9 is capable of a limited rotation by means of a hand-wheel v, worm w, and worm-wheel 1:, this Worm gearing operating within an oil bath y (Figure 3). The oil bath 1 is provided with a filler and inspection cap 11 5 A horizontal slide-way z is formed on a sid face of the slide d, carrying a slide I operated by a hand-wheel 2 and screw 8, and upon this slide l is pivotally mounted an arm 4 carrying a diamond 5, the arm 4 being arranged under control 40 of a clamping lever 8 so as to be capable of being moved forward and lowered into position (as shown in Figure 2) on the peripheral face of the wheel 0 to be trued, in such a manner as to produce intially a true cylindrical surface on the wheel 0 when traversed across its peripheral surface by the hand-wheel 2. In. the operation of the apparatus, the arm of the diamond trueing attachment is set and actuated for the initial trueing of the grinding wheel 0 if this should be necessary, and the speed of the grinding wheel is then reduced considerably below its cutting speed. The swivelling bracket is is then angularly set as shown in Figure 4 by means of its clamping studs m and adlusting screws 0 to suit the helix angle of the work to .be ground, this ensuring the removal by the annular grooves u on the crushing roller 1' of those parts of the wheel 0 which would otherwise interfere with the true form of the finished work. After clamping the bracket k in position the crushing roller 1' is fed by means of the hand-wheel e and screw 1 towards the grinding wheel c along the horizontal slide-way a until'the necessary depth of form can be produced on the wheel 0 by oscillation of the obliquerect-formon the work to be ground, including allowance for interference due to helix angle. It should be note a this arrangement enables one crushing ro r 1' to be used to shape the operative surface of the grinding wheel c for all screw-threads of the same form and pitch, ir.- respective of the diameter of the work-piece.

It will be appreciated that the crushing roller I r may be fitted in various forms for difierent forms and pitch .of surface grooves in the grinding wheel 0, and also that the constructional.

details of the apparatus may be appropriately varied. For example a worm and worm-wheel or other device may be used to adjust the angle of the swivelling bracket in with a fine degree of accuracy, and the tangential oscillation of the crushing roller 1' may'becontrolled by mechanical, electrical, or fluid-pressure mechanism in lieu of the hand-wheel and worm gearing. In-

a further alternative the arrangement may be such that the movement of the grinding wheel head is used to traverse the wheel 0 past the crushing roller 1'.

I claim: 1. A machine for shaping the annularly grooved operative surfaces of grinding wheels for helically grooved work such as screw-threads, and

which comprises, in combination, a frame, a.

horizontal slide-way thereon, a box like slide mounted upon said slide-way, means on said frame for rotatably mounting the grinding wheel a to be grooved and shaped, a .shaft carried by said slide in parallel relation to the axis of rotation of said grinding wheel, an annularly grooved crushing or shaping roller mounted in bearings on said shaft in opposed relation to said grinding wheel, means incorporated in said bearings for swivelling .said roller into an obliquely adjusted setting relative to said axis of the grinding wheel, whereby said roller is accommodated to the helix angle of the work to be eventually ground, means for moving said slide and said roller to and from the operative surface of said grinding wheel, and means for oscillating said obliquely adjusted roller tangentiall'y across the face of said grinding wheel in directions at right angles to said axis to effect the cutting or shaping operation.

2. A machine for shaping the annularly grooved operative surfaces of grinding wheels for helically grooved work such as screw-threads, and which comprises, in combination, a frame, a horizontal slide-way thereon, a' box-like slide mounted upon said slide-way, means on said frame for rotatably mounting the grinding wheel to be grooved and shaped, a shaft carried by said slide in parallel relation to the axis of rotation of said grinding wheel, an annularly grooved crushing or shaping roller mounted in bearings on said shaft in opposed relation to said grinding wheel, means incorporated insaid bearings for swivelling said roller into an obliquely adjusted setting relative to said axis of the grinding wheel, whereby said roller is accommodated to the helix angle of the work to be eventually ground, means for moving said slide and said roller to and from the operative surface of said grinding wheel, means for oscillating said obliquely adjusted roller tangentially across the face of said grinding wheel in directions at right angles to said axis to'efi'ect the cutting or shaping operation, and a diamond trueing attachment carried by said slide for producing a true cylindrical surface on said grinding wheel prior to the formation and shaping of the annular grooves thereon.

ARTHUR SCRIVENER. 

